If "Transforming Sphere" is equipped with a monster like "Vanity's Fiend" or with a Special Summon Monster like "Dark Armed Dragon" that cannot be Special Summoned, then during the End Phase the effect to Special Summon the equipped monster to your opponent's field still activates. However, the monster cannot be Special Summoned, so it is sent to the Graveyard. Similarly, if you cannot Special Summon during the End Phase - for example, if the effect of "Vanity's Fiend" is active, or if you activated "Scapegoat" during this turn - then the effect of "Transforming Sphere" still activates during the End Phase, but the equipped monster is sent to the Graveyard since it cannot be Special Summoned.[4]

Previously Official Rulings

These TCG rulings were issued by Upper Deck Entertainment and have since been deemed unofficial by Konami.[5] They were previously considered official and can still be correct, as long as they follow the official gameplay rules, or unless Konami has issued a ruling that says otherwise. References: [6][7][8][9][10][11][12][13][14]

You can only activate "Scapegoat" if you have 4 or more vacant Monster Card Zones.

If the effect of "Cyber Jar" is activated during the turn you already activated "Scapegoat" all monsters that could be Special Summoned will be sent to the Graveyard.

If you control 2 monsters and your opponent activates "Change of Heart" to gain control of one and you later activate "Scapegoat" your monster will be destroyed during the End Phase if all 5 of your Monster Card Zones are still occupied.

Mentions in Other Rulings

Asura Priest: "Asura Priest" cannot attack a monster if it has already attacked directly this turn. For example, the opponent activates..."Scapegoat" after "Asura Priest" has completed a direct attack.

Chain Disappearance: The effect of "Chain Disappearance" can remove multiple monsters that are Summoned simultaneously, for example if your opponent activates "Scapegoat", you can respond with "Chain Disappearance" to remove all 4 "Sheep Tokens" that were Special Summoned from the field.

Cocoon Veil: You cannot activate this card if you cannot Special Summon a monster due to the effect of "Scapegoat", etc.

Conscription: If you cannot Summon because you activated "Scapegoat"...that turn, you cannot activate "Conscription".

Goldd, Wu-Lord of Dark World / Sillva, Warlord of Dark World: "Goldd, Wu-Lord of Dark World" / "Sillva, Warlord of Dark World" must be Special Summoned to resolve the second part of his effect. If you cannot Summon him because you activated "Scapegoat" that turn, or your Monster Card Zones are full, then the second part of his effect does not resolve.

Hero Counterattack: You cannot activate this card if you cannot Special Summon a monster due to the effect of "Scapegoat", etc.

Jam Breeding Machine: You cannot activate "Scapegoat" if you have this card active on your side of the field.

Light and Darkness Dragon: If you cannot Special Summon a monster because of a card’s effect (“Scapegoat”, etc.) when “Light and Darkness Dragon” is destroyed and sent to the Graveyard you will not be able to Special Summon the selected monster but you must still destroy every card that you control.

Metamorphosis: You can Tribute a Monster Token (including a Sheep Token from "Scapegoat").

Ojama Trio: You cannot activate "Ojama Trio" if "Scapegoat"...is preventing you from Summoning.

Reasoning: You cannot activate "Reasoning" if you already activated "Scapegoat" this turn.

Spatial Collapse: While "Spatial Collapse" is active and you have 1 or more cards already on your side of the field, you cannot activate "Scapegoat" because you would have your 1 previous card + the "Scapegoat" card + 4 monster tokens = 6.

Torrential Tribute: "Torrential Tribute" can be activated after a monster is Summoned through another card's effect, such as..."Scapegoat"...

Twin-Headed Behemoth: If "Twin-Headed Behemoth" would be Special Summoned by its own effect, but your Monster Card Zones are full, or the effect of "Scapegoat" prevents you from Summoning, it still considered that its effect was activated, and you cannot use it again in the current Duel.

Vanity's Fiend: Cards like "Scapegoat"...cannot be activated while "Vanity's Fiend" is on the field.

Wild Fire: You cannot activate "Wild Fire" if you are prevented from Special Summoning monsters, due to an effect like "Scapegoat".

References

↑ 1.01.1Konami FAQ: If you cannot Special Summon because of the effect of "Scapegoat" etc, can the effect of "Gallis the Star Beast" be activated?